Anthrax pneumonia A22.1+J17.0*

Discoverer of the pathogen: Koch, 1876; the disease "anthrax" has been known since ancient times. It is generally believed that the fifth and sixth plagues of Egypt, described in the Book of Exodus, were due to anthrax.Both Homer and Ovid reported it. In older Arabic writings, anthrax is referred to as "Persian fire." The name anthrax refers to the dark-colored and burnt-looking spleen of diseased animals.

Based on studies of anthrax, Koch made his famous postulates in 1876. Vaccines against anthrax - most famously that of Pasteur (1881) - were among the first bacterial vaccines developed.

A zoonosis with Bacillus anthracis that is widespread worldwide, very rarely occurring in humans, and is notifiable (suspicion, disease and death). Misuse as a biological warfare agent.

The disease anthrax manifests itself in 4 main forms:

Pulmonary anthrax (incubation period 4-6 days after inhalation of the germs)

skin anthrax (incubation period hours to a few days after cutaneous inoculation of the germs) - most frequent manifestation form of anthrax (95% of all anthrax cases)

Gastrointestinal anthrax (incubation period 1-3 days after oral uptake of the germs)

Injection anthrax (incubation time 1-3 days after injection of the germ-containing material)

Bacillus anthracis is a gram-positive, aerobic, rod-shaped bacterium from the Bacillaceae family with the ability to produce toxins and capsules. The bacteria have a length of approximately 4 μm and a width of 1 µm. They form chains (up to 6 - 8 cells in the blood of infected organisms). Bacillus anthracis is a spore former. The spores are extremely resistant. They have a size of approx. 1 x 2 μm and germinate into vegetative cells as soon as they are in a suitable environment, such as blood. Under growth-limiting conditions (e.g. after release of the cells from an infected animal) they form spores again.

Virulence is based on the ability to form exotoxins and capsules, which are encoded by two plasmids, pXO1 and pXO2. The vegetative forms produce 3 protein components important for toxin formation:

• Protective antigen (PA)
• lethal factor (LF) and
• Edema factor (EF-Edema Factor).

The combination of PA and EF leads to the formation of the edema toxin (EdTx), the combination of PA and LF to the lethal toxin (LeTx). The toxins are responsible for local edema formation and necrotic tissue damage (see also skin anthrax).

Spread throughout the world, especially in livestock areas (ruminants). Very rarely in industrialized countries; preferred in warmer climates, e.g. in Southeast Europe, South America, Africa, Southeast Asia. Herbivorous farm and wild animals are thus primarily affected by the intake of the zoonotic agent and are involved in its further spread. In Germany, twelve cows died of anthrax in July 2012 in Saxony-Anhalt. In other countries anthrax is more common in animals, e.g. in the Balkan states, Southern Europe (including Turkey), Central Asia and Southern Africa. In West Africa, highly virulent pathogens have been detected in connection with the death of great apes, which must be assigned to the bacterial species B. cereus due to the chromosomal DNA. However, these bacteria contain virulence plasmids of B. anthracis. This pathogen has therefore been named B. cereus biovar anthracis (Hoffmaster AR et al.2004).

Infection through contact with spores of the pathogen Bacillus anthracis from contaminated animal materials (organs, fur, wool, fertiliser with bone meal). No infection from person to person! The spores are extremely resistant and can survive for years in animal products or in the animal environment (pastures, stables, feed). After inoculation of the spores (skin injury, inhalation or consumption) the growth of the pathogen begins and a protein capsule is formed which protects it from phagocytosis. It also produces various exotoxins (lethal toxin, edema toxin).

The virulence factors of B anthracis are its capsule and the three-component toxin, both of which are encoded on plasmids. Bacillus cereus produces numerous enzymes and aggressins. The major virulence factors are anecrotizing enterotoxin and a potent hemolysin (cereolysin). Nausea-causing food poisoning probably results from the release of emetic factors from certain foods by bacterial enzymes.

The reasons for marked differences in susceptibility to anthrax in different animal species are not known. The protective effect of the live spore vaccine for animals or the chemical human vaccines is based on the induction of humoral and cell-mediated immunity against the protective antigenic component of the anthrax toxin.

After inhalation of dust or aerosols containing spores, within a few hours or a few days a severe bronchopneumonia with high fever, chills, bloody cough, hypoxia occurs. The bloody sputum can be infectious. If left untreated, pulmonary anthrax can be fatal within 2-3 days.

Pathogen detection from blood and tissue samples. PCR. If possible, the tests should be carried out in so-called reference centres for anthrax (e.g. RKI in Berlin). Antibodies can also be detected at a later stage.

Anthrax meningitis: possible complication in all forms of manifestation (up to 50% of cases). Foudroyant course with headache, high fever and loss of consciousness

In case of suspicion: 100-day prophylactic therapy of all potentially exposed persons with ciprofloxacin 2x500mg p.o./day or doxycycline 2x100mg p.o./day (or amoxicillin in pregnant women) in combination with clindamycin or rifampicin.

The risk of transmission from person to person is generally very low. In principle, however, there is a possibility of transmission from contaminated clothing or direct contact with body fluids (especially wounds - Doganay M et al. 2010). Therefore, all measures of standard hygiene should be strictly implemented. Hand contamination should be avoided by wearing protective gloves and using the non-touch technique whenever possible. Additionally, strict hand hygiene.

Hand/surface and instrument disinfection procedures: Attention should be paid to spore efficacy. In experimental approaches, good (e.g., use of peracetic acid products).

The use of further personal protective equipment (protective gown, mouth-nose protection, eye protection) can further reduce the very low risk of transmission.

After surgical procedures, instruments must be reprocessed according to the procedure recommended by the RKI against spores of anthrax (effect area C) (RKI (2007). Currently, no chemical disinfectants are listed, only thermal procedures with effect area C.

Further segregation measures: Contact persons or suspects of infection do not need to be segregated. However, in addition to possible postexposure measures, close self-observation - with medical advice if necessary - should be carried out for suspected infected persons throughout the incubation period in order to recognize possible symptoms immediately. Patients should, if possible, be accommodated in a single room to exclude the minimal residual risk of transmission.

Since June 2013, an anthrax emergency vaccine (trade name BioThrax®) has been available in Germany(Emergent BioSolutions).

The largest known outbreak of anthrax occurred in Russia (Yekaterinburg) in 1979. The outbreak occurred after an accident at a bioweapons factory. Of the 79 employees who inhaled the anthrax spores, 68 survived. Also unknown is the exact number of countries that have anthrax. It is likely that several countries have anthrax spores available as a bioweapon.

Thus, anthrax spores have been repeatedly misused as bioterrorist weapons in the past. In 2001, several letters contaminated with the pathogen appeared in the USA. As a result, 22 people fell ill and five died. Thousands of people, mainly postal workers, were advised to take antibiotics against anthrax as a preventive measure. Anthrax is considered a significant threat by public health authorities worldwide, both through normal infection routes and through bioterrorism.

In Germany and other European countries, anthrax occurs only sporadically.

Isolated infections have been reported in 2009 - 2012 (predominantly drug users; causative agent was presumably contaminated heroin - (Ringertz SH et al. 2010; Booth MG et al.2010). Molecular comparisons of the outbreak strains of different injection anthrax cases indicate that it was probably the same strain of anthrax (Bernard H 2010).

1. Bernard H (2010) Drug use: Bacillus anthracis in heroin? German Ärztebl 107:703
2. Booth MG et al(2010) Anthrax infection in drug users. Lancet 375:1345-1346
3. Doganay M et al (2010) A review of cutaneous anthrax and its outcome. J Infect Public Health 3: 98-105
4. Hoffmaster AR et al (2004) Identification of anthrax toxin genes in a Bacillus cereus associated with an illness resembling inhalation anthrax. Proc Natl Acad Sci U S A 101:8449-854
5. Ringertz SH et al (2010) Injectional anthrax in a heroin skin-popper. Lancet 356: 1574-1575
6. RKI (2007) List of disinfectants and disinfection methods tested and approved by the Robert Koch Institute.
7. RKI Guide - Robert Koch Institute